Multiple cells express interleukin 17 in oral squamous cell carcinoma

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Interleukin-17 (IL-17) is a pro-inflammatory cytokine with complex roles in cancer, exhibiting both pro- and anti-tumor effects.
• Understanding the presence and cellular sources of IL-17 in oral squamous cell carcinoma (OSCC) is crucial for elucidating its role in tumor pathogenesis.

Purpose of the Study:

• To investigate the presence and quantify IL-17-expressing cells in OSCC tissues.
• To identify the potential cellular sources of IL-17 within the OSCC microenvironment.
• To analyze the spatial distribution of IL-17-positive cells in relation to tumor compartments.

Main Methods:

• Immunohistochemistry and double-labeling immunofluorescence were employed to detect and characterize IL-17-positive cells in OSCC and control tissues.
• Laser scanning microscopy was used to identify specific cell types co-expressing IL-17.
• Sandwich ELISA was utilized to assess IL-17 production by OSCC cell lines in vitro.

Main Results:

• OSCC tissues exhibited significantly higher numbers of IL-17-positive cells compared to inflammatory controls (P < 0.0001).
• IL-17-positive cells were found in tumoral islands, tumor-stroma interface, and distant stroma, with a higher concentration in the stroma compared to tumoral islands (P < 0.01).
• Helper T cells, cytotoxic T cells, macrophages, and mast cells were identified as IL-17 co-expressing cells; OSCC cell lines did not produce detectable IL-17.

Conclusions:

• Tumor cells themselves do not express IL-17; rather, a variety of immune and stromal cells contribute to IL-17 levels in OSCC.
• The distribution of IL-17-positive cells suggests interactions within the tumor microenvironment, indicating a potential role for IL-17 in OSCC development.
• These findings highlight the multifaceted role of IL-17 in OSCC and suggest therapeutic targeting of IL-17-producing cells.